Nano scale contribution to features occurring at micro scale in lubricated contacts - Archive ouverte HAL Access content directly
Conference Papers Year : 2014

Nano scale contribution to features occurring at micro scale in lubricated contacts

Philippe Vergne
  • Function : Author
  • PersonId : 839328
Daniele Savio
  • Function : Author
  • PersonId : 764837
  • IdRef : 176609148
Nicolas Fillot


Nowadays the thickness of the film separating two lubricated surfaces can decrease down to a few nanometers thus becoming comparable with the size of the fluid molecules. Under such severe confinement, the continuum hypothesis upon which the traditional lubrication models are based may not be valid anymore. Understanding the properties of nanometer-thin lubricant films has thus been a major concern in the past 20 years, leading to the development of experimental and numerical methods capable of accessing quantities at the molecular scale. The current challenge consists to take into account the results in real-size contacts. The integration of nano scale effects into the lubrication theory would allow unraveling the influence played by molecularly thin films on the global contact behavior. The main difficulty arises from the significant difference in scale between the atomistic simulation methods (for instance Molecular Dynamics) which are limited to some nanometers, and the existing continuous models for lubricated contacts of the order of one millimeter in size. A promising way to overcome this issue involves deriving the results of nano scale simulations through representative expressions, which can then be straightforwardly coupled to the equations of the classical lubrication theory in which a Navier-type boundary condition is imposed. This multi-scale coupling strategy was successfully applied [1] to reflect the influence of wall-slip (quantified from MD simulations as a function of macro scale parameters like pressure, sliding velocity and thickness) onto a macro scale contact lubricated by a simple hydrocarbon fluid. The continuous problem was solved on the basis of a FE method solver [2]. This approach is now extended to more realistic situations in which firstly the wall-slip characterization was more extensively studied [3] and parameterized using atomistic simulations, and secondly the composition and thus the wettability of the bounding surfaces were considered as input parameters. According the different cases investigated, significant modifications of the film thickness profiles, fluid mass flow and friction were observed in the resulting thin films. All in all we propose a way to bridge the gap between nano and macro scale simulations for lubricated contacts.
Not file

Dates and versions

hal-01079491 , version 1 (02-11-2014)


  • HAL Id : hal-01079491 , version 1


Philippe Vergne, Daniele Savio, Nicolas Fillot. Nano scale contribution to features occurring at micro scale in lubricated contacts. 7th International Conference, on Multiscale Materials Modeling, Institute of Physics, Oct 2014, Berkeley CA, United States. ⟨hal-01079491⟩
62 View
0 Download


Gmail Facebook Twitter LinkedIn More